Water (h2o) is composed of the same elements as hydrogen peroxide (h2o2) why do these substances have different properties a.) the atoms are arranged differently in each molecule b.) the molecules are the same c.) the atoms are the same d.) water has more atoms than hydrogen peroxide

Option A is correct;

A.) The atoms are arranged differently in each molecule

Water and hydrogen peroxide are made of the same elements: oxygen and hydrogen. However, hydrogen peroxide (H2O2) has 1 more oxygen than water (H2O).

Hydrogen peroxide is very unstable and breaks down readily into water and a single oxygen molecule.

And also the arrangement of atoms is different in each molecule.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol